There has been recently provided a power storage apparatus to be used in a consumer's facility. Furthermore, there has been also proposed an energy management system that is capable of obtaining a price by a negotiated trade with an electric power provider, or a trade of an electric power adjusting reservation capacity in a power market, as a adjusting reservation capacity for a demand response (see e.g., JP 2012-165513 A (hereinafter referred to as “Document 1”)).
Document 1 discloses a technique for generating a reduction schedule for facilities of consumers to meet the power consumption reduction amount, using a generated power amount of a power generation apparatus, a discharged power amount of a power storage apparatus and the like.
Incidentally, in a consumer's facility, a cost at introduction of a power storage apparatus capable of supplying power to an electric load is high. The high cost is a factor in a hindrance to spreading a power storage apparatus. With the technique disclosed in Document 1, the price can be obtained by meeting a request of the demand response, but it is necessarily impossible to provide a sufficient motivation for promoting spread of a power storage apparatus.